ABOS Part I Comprehensive Review - Batch 8

Question 1

A 38-year-old male presents to the emergency department after a fall onto an outstretched hand. A lateral radiograph of the wrist is obtained, as shown below.Based on this image, which of the following best describes the carpal injury?

Accepted Answer

Perilunate dislocation with dorsal displacement of the capitate relative to the lunate.

Question 2

A 45-year-old carpenter falls from a roof, landing on his outstretched hand with the wrist in hyperextension and ulnar deviation. This mechanism typically initiates a progressive pattern of ligamentous injury around the lunate. According to Mayfield'

Accepted Answer

Scapholunate interosseous ligament

Question 3

A 32-year-old athlete presents with an acute perilunate dislocation after a snowboarding accident. On examination, he complains of numbness and tingling in the radial three and a half digits, and weakness in thumb opposition and abduction. What is th

Accepted Answer

Perform immediate closed reduction of the wrist.

Question 4

In the context of a perilunate dislocation, which carpal bone fracture is most frequently observed in conjunction with the ligamentous injury, often leading to a 'greater arc' injury pattern?

Accepted Answer

Scaphoid fracture

Question 5

A 28-year-old male is diagnosed with an acute perilunate dislocation in the emergency department. After ensuring patient stability and providing adequate analgesia, what is the most critical immediate next step in his management?

Accepted Answer

Attempt prompt closed reduction, typically under sedation.

Question 6

A 55-year-old patient presents with a chronic, unreduced perilunate dislocation, diagnosed 8 months after his initial injury. He complains of severe pain, stiffness, and weakness. Radiographs show significant degenerative changes in the radiocarpal j

Accepted Answer

Proximal row carpectomy (PRC).

Question 7

Following successful closed reduction of a perilunate dislocation, a post-reduction PA radiograph of the wrist is obtained, as depicted below.Despite apparent overall carpal alignment, what does the finding highlighted in the image most strongly sugg

Accepted Answer

Persistent scapholunate dissociation (Terry Thomas sign).

Question 8

During open reduction and internal fixation of an acute perilunate dislocation, the surgeon aims to repair the disrupted dorsal capsuloligamentous structures and stabilize the scapholunate joint. Which surgical approach provides the most direct and e

Accepted Answer

Dorsal approach, typically between the third and fourth extensor compartments.

Question 9

An untreated or chronically missed perilunate dislocation is highly likely to lead to a specific pattern of progressive carpal collapse and degenerative arthritis. Which of the following long-term complications is most characteristic of this natural

Accepted Answer

Scapholunate Advanced Collapse (SLAC) or Scaphoid Nonunion Advanced Collapse (SNAC) wrist.

Question 10

Following open reduction and internal fixation of a perilunate dislocation, K-wires are typically placed across the scapholunate and capitolunate joints. What is the primary purpose of these K-wires, and for approximately how long are they usually ma

Accepted Answer

To maintain anatomical reduction and protect ligament repairs during healing; 8-12 weeks.

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Key Takeaway